A technology has been known which allows one information processing apparatus to start another information processing apparatus in a system containing a plurality of connected information processing apparatuses. Examples of the system containing a plurality of connected information processing apparatuses include a storage system containing a basic apparatus and an extension apparatus, which are connected to each other. The basic apparatus controls an access request from an external apparatus. The extension apparatus controls an access request from the basic apparatus to a storage within the extension apparatus.
In order to add a storage to a storage system, an extension apparatus may be connected to a basic apparatus. The extension apparatus to be added may be connected by serial connection, for example. In a storage system containing an extension apparatus connected to a basic apparatus, the basic apparatus can desirably start the extension apparatus.
In order for the basic apparatus to start an extension apparatus, a special line for power control may be provided between the basic apparatus and the extension apparatus. Alternatively, a controller may run at all times within the extension apparatus. In this case, the controller connected communicably to the basic apparatus, controls accesses to a storage apparatus within the extension apparatus and starts a storage on the basis of communication with the basic apparatus. When an extension apparatus is serially connected to the basic apparatus, the started extension apparatus may start the subsequently connected extension apparatus and sequentially start a plurality of extension apparatuses.
Japanese Laid-open Patent Publication (Translation of PCT Application) No. 2007-503791 and Japanese Laid-open Patent Publication No. 2005-250739 are examples of related art.
However, a communication interface between the basic apparatus and an extension apparatus may not always have a signal for power control. Thus, when a communication interface without a signal for power control is used, a special line for power control may not be provided between the basic apparatus and an extension apparatus as described above.
Within an extension apparatus, an unignorable amount of power may be consumed by operations by a controller that is communicably connected to the basic apparatus and controls accesses to a storage apparatus within the extension apparatus.
In this way, the technology in the past may not sufficiently suppress the power consumption at a standby state in a communication interface without a signal for power control.
The disclosed art was made in view of the aforementioned situations, and it is an object of the present invention to provide a storage system, storage apparatus and storage-apparatus starting method that suppress power consumption at a standby state and allows power interlocking between apparatuses, without using a signal for power control.